Dietary Genistein Inactivates Rat Thyroid Peroxidase in Vivo without an Apparent Hypothyroid Effect

2000 ◽  
Vol 168 (3) ◽  
pp. 244-252 ◽  
Author(s):  
Hebron C. Chang ◽  
Daniel R. Doerge
Keyword(s):  
Thyroid Peroxidase ◽  
Rat Thyroid

Effect of serum thyrotropin levels on the concentration of messenger RNA for thyroid peroxidase in the rat

1992 ◽  
Vol 126 (5) ◽  
pp. 460-466 ◽  
Author(s):  
Ronald P Magnusson ◽  
Bo Yu ◽  
Veronica Brennan
Keyword(s):  
Messenger Rna ◽  
Thyroid Peroxidase ◽  
Mrna Levels ◽  
Hypophysectomized Rats ◽  
Steady State Levels ◽  
Low Levels ◽  
Rat Thyroid ◽  
Serum Tsh ◽  
Bovine Tsh

The effect of serum TSH on rat thyroid peroxidase mRNA levels was studied in order to investigate the regulation of thyroid peroxidase gene expression in vivo. A nearly full-length rat thyroid peroxidase cDNA clone was isolated from a bacteriophage cDNA library synthesized using poly A+ RNA isolated from the thyroids of propylthiouracil-treated rats. cDNA probes derived from this clone were used to study rat thyroid peroxidase mRNA levels in response to the level of serum TSH. Two major rat thyroid peroxidase mRNA bands were detected on Northern blots of total cellular RNA (at 3.2 kb and at 3.7kb). Injection of thyroxine, which lowered the levels of serum TSH, also lowered the steady-state levels of both rat thyroid peroxidase mRNAs, whereas treatment with methimazole, which increased serum TSH, increased both rat thyroid peroxidase mRNA levels. In hypophysectomized rats 10 days postoperative, very low levels of thyroid peroxidase mRNA were observed. Injection of bovine TSH (1 IU/day) increased rat thyroid peroxidase mRNA expression, preferentially in the 3.2 kb band. These results clearly demonstrate that TSH regulates rat thyroid peroxidase mRNA levels in vivo.

scholarly journals APPEARANCE AND FUNCTION OF ENDOGENOUS PEROXIDASE IN FETAL RAT THYROID

1971 ◽  
Vol 51 (1) ◽  
pp. 162-175 ◽  
Author(s):  
Judy M. Strum ◽  
Janice Wicken ◽  
John R. Stanbury ◽  
Morris J. Karnovsky
Keyword(s):  
Apical Cell ◽  
Thyroid Peroxidase ◽  
Follicular Cells ◽  
Thyroid Follicle ◽  
Apical Cell Membrane ◽  
Fetal Rat ◽  
Apical Vesicles ◽  
Rat Thyroid ◽  
And Function

Iodination within the thyroid follicle is intimately associated with a thyroid peroxidase. In order to locate the in vivo site of iodination, the initial cytochemical appearance of this enzyme has been determined in fetal rat thyroid and its presence correlated with the onset of iodinated thyroglobulin synthesis. Peroxidase first appears in follicular cells during the 18th day of gestation. It is seen first in the perinuclear cisternae, the cisternae of the endoplasmic reticulum, and within the inner few Golgi lamellae. These organelles presumably represent sites of peroxidase synthesis. During the 19th and 20th days of gestation, there is a tremendous increase in peroxidase activity. In addition to the stained sites described, there are now many peroxidase-positive apical vesicles in the follicular cells. Newly forming follicles stain most conspicuously for peroxidase, the reaction product being heavily concentrated at the external surfaces of apical microvilli and in the adjacent colloid. Iodinated thyroglobulin becomes biochemically detectable in thyroids during the 19th day of gestation and increases greatly during the 20th day. The parallel rise in peroxidase staining that just precedes, and overlaps, the rise in iodinated thyroglobulin, suggests that apical vesicles and the apical cell membrane are the major sites of iodination within the thyroid follicle.

Tri-iodothyronine increases insulin-like growth factor binding protein-4 expression in rat hepatocytes

1997 ◽  
Vol 154 (1) ◽  
pp. 155-165 ◽  
Author(s):  
I Demori ◽  
C Bottazzi ◽  
A Voci ◽  
G Gallo ◽  
J-G Scharf ◽  
...  
Keyword(s):  
Growth Factor ◽  
Binding Protein ◽  
Mrna Level ◽  
Insulin Like Growth Factor ◽  
Cultured Hepatocytes ◽  
Adult Rats ◽  
Direct Role ◽  
Factor Binding ◽  
Rat Thyroid

Abstract Previous in vivo studies demonstrated significant variations in insulin-like growth factor binding protein-1 (IGFBP-1), IGFBP-2 and IGFBP-4 hepatic mRNAs and/or serum levels depending on the rat thyroid status. In this study we employed cultured hepatocytes from adult rats to demonstrate a possible direct regulation of these genes by tri-iodothyronine (T3). Northern blot analysis revealed that IGFBP-1 and -4 messages were clearly expressed, whereas IGFBP-2 signal was barely detectable. No significant effects on IGFBP-1 mRNA level or on peptide secretion were detected in T3-cultured hepatocytes. In contrast, significant increases in IGFBP-4 mRNA steady-state levels as well as in IGFBP-4 secretion were observed in hepatocytes cultured for 12–24 h in the presence of T3. The T3 effect on IGFBP-4 transcript levels appears to consist of enhanced gene transcription and is independent of ongoing protein synthesis. The T3-increased IGFBP-4 expression in cultured hepatocytes is consistent with our in vivo experiments demonstrating an increase in hepatic IGFBP-4 mRNA and serum IGFBP-4 levels in T3-treated rats. Furthermore, significant decreases in hepatic IGFBP-4 message and serum IGFBP-4 levels were observed in hypothyroid rats compared with euthyroid controls. Our data establish an important direct role for thyroid hormone in regulating IGFBP-4 expression and consequently IGF activity. Journal of Endocrinology (1997) 154, 155–165

IN VIVO LOCALISATION OF RADIOLABELLED ANTIBODIES TO RAT THYROGLOBUL IN IN THE 1-1C2 RAT THYROID TRANSPLANTABLE TUMOUR

1982 ◽  
Vol 3 (1) ◽  
pp. 4-12 ◽  
Author(s):  
M. Schlumberger ◽  
A. J. Van Herle ◽  
R. Di Paola ◽  
A. Vignal ◽  
M. Di Paola ◽  
...  
Keyword(s):  
Radiolabelled Antibodies ◽  
Transplantable Tumour ◽  
Rat Thyroid

Rat Thyroid Peroxidase (Tpo) Biosynthesis in Vitro: Studies Using Antiserum to Porcine Tpo

1987 ◽  
Vol 13 (1) ◽  
pp. 15-29 ◽  
Author(s):  
David S. Cooper ◽  
Farahe Maloof ◽  
E. Chester Ridgway
Keyword(s):  
In Vitro Studies ◽  
Thyroid Peroxidase ◽  
Rat Thyroid

Acute and chronic leptin effect upon in vivo and in vitro rat thyroid iodide uptake

Life Sciences ◽  
2007 ◽  
Vol 81 (15) ◽  
pp. 1241-1246 ◽  
Author(s):  
Elaine de Oliveira ◽  
Aline Teixeira Silva Fagundes ◽  
Isabela Teixeira Bonomo ◽  
Flavio Henrique Curty ◽  
Magna Cottini Fonseca Passos ◽  
...  
Keyword(s):  
Iodide Uptake ◽  
Rat Thyroid

scholarly journals Acrylamide does not induce tumorigenesis or major defects in mice in vivo

2008 ◽  
Vol 198 (2) ◽  
pp. 301-307 ◽  
Author(s):  
Ling Jin ◽  
Vanessa Chico-Galdo ◽  
Claude Massart ◽  
Christine Gervy ◽  
Viviane De Maertelaere ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Chronic Administration ◽  
Serum Levels ◽  
Human Thyroid ◽  
Thyroid Cell ◽  
Thyroid Cells ◽  
Hormone Synthesis ◽  
Rat Thyroid

Chronic administration of acrylamide has been shown to induce thyroid tumors in rat. In vitro acrylamide also causes DNA damage, as demonstrated by the comet assay, in various types of cells including human thyroid cells and lymphocytes, as well as rat thyroid cell lines. In this work, mice were administered acrylamide in their drinking water in doses comparable with those used in rats, i.e., around 3–4 mg/kg per day for mice treated 2, 6, and 8 months. Some of the mice were also treated with thyroxine (T4) to depress the activity of the thyroid. Others were treated with methimazole that inhibits thyroid hormone synthesis and consequently secretion and thus induces TSH secretion and thyroid activation. These moderate treatments were shown to have their known effect on the thyroid (e.g. thyroid hormone and thyrotropin serum levels, thyroid gland morphology…). Besides, T4 induced an important polydipsia and degenerative hypertrophy of adrenal medulla. Acrylamide exerted various discrete effects and at high doses caused peripheral neuropathy, as demonstrated by hind-leg paralysis. However, it did not induce thyroid tumorigenesis. These results show that the thyroid tumorigenic effects of acrylamide are not observed in another rodent species, the mouse, and suggest the necessity of an epidemiological study in human to conclude on a public health policy.

scholarly journals Ultrastructure of blebbing and phagocytosis of blebs by hyperplastic thyroid epithelial cells in vivo.

1977 ◽  
Vol 72 (3) ◽  
pp. 584-594 ◽  
Author(s):  
J D Zeligs ◽  
S H Wollman
Keyword(s):  
Thyroid Gland ◽  
Epithelial Cells ◽  
Cultured Cells ◽  
Ultrastructural Organization ◽  
Contractile Ring ◽  
Phagocytic Process ◽  
Different Types ◽  
Rat Thyroid

In addition to pseudopods, somewhat pleomorphic blebs were consistently found protruding from the apical surfaces of hyperplastic rat thyroid epithelial cells into the follicular lumens in vivo. Many blebs were knobby, roughly hemispherical protrusions, with a diameter of 2-3 mum. Such blebs had a densely packed microfilamentous core and contained numerous apparent ribosomes. They were morphologically similar to blebs that have been observed in a variety of cultured cells. Other blebs were larger, more elongate, and less knobby, but had a similar ultrastructural organization. Blebs of all sizes appeared to be phagocytosed on some occasions by nearby epithelial cells. The phagocytic process involved partial engulfment of the bleb by a typical epithelial pseudopod, followed by an apparent pinching-off process, presumably resulting in the separation of the bleb from its cells or origin. The pinching-off process was associated with a band of approx. 6-nm diameter microfilaments that developed within the pseudopod cytoplasm surrounding the base of the bleb and is postulated to function as a contractile ring. The finding of blebbing is an intact tissue in vivo indicates that this phenomenon is not restricted to cultured cells, and thus tends to extend the significance of in vitro observations of the process. In relation to their occurrence in the hyperplastic thyroid gland in vivo, possible interconversions are considered between different types of blebs, and between blebs and pseudopods.

Contribution of R domain phosphoserines to the function of CFTR studied in Fischer rat thyroid epithelia

2000 ◽  
Vol 279 (5) ◽  
pp. L835-L841 ◽  
Author(s):  
Olafur Baldursson ◽  
Herbert A. Berger ◽  
Michael J. Welsh
Keyword(s):  
Functional Role ◽  
Transmembrane Conductance Regulator ◽  
Regulatory Domain ◽  
Wild Type ◽  
Transmembrane Conductance ◽  
Dependent Protein ◽  
Rat Thyroid ◽  
Cystic Fibrosis Transmembrane

The regulatory domain of cystic fibrosis transmembrane conductance regulator (CFTR) regulates channel activity when several serines are phosphorylated by cAMP-dependent protein kinase. To further define the functional role of individual phosphoserines, we studied CFTR containing previously studied and new serine to alanine mutations. We expressed these constructs in Fischer rat thyroid epithelia and measured transepithelial Cl− current. Mutation of four in vivo phosphorylation sites, Ser660, Ser737, Ser795, and Ser813 (S-Quad-A), substantially decreased cAMP-stimulated current, suggesting that these four sites account for most of the phosphorylation-dependent response. Mutation of either Ser660 or Ser813 alone significantly decreased current, indicating that these residues play a key role in phosphorylation-dependent stimulation. However, neither Ser660 nor Ser813 alone increased current to wild-type levels; both residues were required. Changing Ser737 to alanine increased current above wild-type levels, suggesting that phosphorylation of Ser737 may inhibit current in wild-type CFTR. These data help define the functional role of regulatory domain phosphoserines and suggest interactions between individual phosphoserines.

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